Flexible water gate

ABSTRACT

A flexible water gate is described that is suitable for retaining water in a port, canal or river estuary. The gate is both economical to build and maintain and comprises a gate controller that allows a flexible member to be controllably moved between a closed and open position, as required. A flexible flood control barrier that comprises one or more of the aforementioned flexible water gates is also described. These gates are deployed side to side and provide an economical way of providing flood protection to an area susceptible to flood tides. When not in use the flexible membranes of the flexible water gates can be stored on the riverbed so permitting unrestricted access for marine vessels.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is the national phase of International (PCT) PatentApplication Serial No. PCT/GB02/05579, filed Dec. 9, 2002, publishedunder PCT Article 21(2) in English, which claims priority to and thebenefit of British Patent Application No. 0129435.4, filed Dec. 8, 2001,the disclosures of which are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to the field of water gates. Inparticular, it relates to a water gate made from a flexible membrane foruse within a port, canal or river estuary.

BACKGROUND OF THE INVENTION

Water gates are employed in a range of impound docks, marinas and canalsin order to protect vessels from the detrimental effects of tides, windand waves. Similarly such gates are employed within lock mechanisms soas to permit vessels to move up and down from one water level to anotherwithin a canal.

A further area where water gates are employed is in the construction offlood control barriers. Typically, a number of gates are located acrossa river estuary and are deployed at times when tide levels rise to sucha point that there is a significant danger of flooding of thesurrounding area.

In order for existing flood control barriers designs to provide thenecessary protection their construction requires substantial civilengineering work that includes the installation of concrete caissons. Agood example of such a flood control barrier is the Thames Barrier. Suchstructures are therefore extremely expensive and their installation canseriously disturb the habitat of the sub-sea life forms and thesurrounding environment.

The Prior Art teaches of Mitre, Sector, Radial and Flap style watergates employed for the aforementioned purposes. These all comprise steelcore structures with various means for providing the required watertightseal. However, for various reasons these gate designs are prone toleakage.

In the UK alone 73% of ports that employ Mitre gates exhibit substantiallevels of leakage. Such leaks cost time and the associated water lossescan render the port unattractive and ultimately inoperable. Replacementgates cost in the region of .English Pound.800,000 and have a lifetimeof about 30 to 50 years. However, Mitre gates require major maintenancework every 10 to 15 years that typically incurs costs of .EnglishPound.200,000.

In addition the effects of global warming are reducing the efficiency ofMitre gates due to increases in the associated water levels. These gatesdepend upon hydraulic pressure that results from the difference in thewater levels from the upper side and lower side of the Mitre gate. Suchincreased water levels act to reduce this difference hence reducing thegate efficiency.

A second disadvantage of such gate designs is the fact that they employhardwoods in order to provide the required watertight seals. These woodsare expensive due to their limited supply and so a more environmentallyfriendly solution would be preferable.

Presently, Sector gates are the preferred option for replacing MitreGates. Although the gates themselves offer an economical alternative tothe Mitre Gate they require extensive civil engineering work to becarried out to provide the required Sector gate recesses. Such civilengineering is both time consuming and expensive incurring costs ofseveral millions of pounds.

BRIEF SUMMARY OF THE INVENTION

It is an object of the present invention to provide a flexible watergate suitable for retaining water in a port, canal or river estuary thatis economical to build and maintain while providing a controllable meansfor deploying the gate when required.

It is a further object of the present invention to provide a flexibleflood control barrier comprising one or more flexible water gates thatcan be controllably deployed at times when tide levels rise to producean imminent risk of flooding of the surrounding area.

According to a first aspect of the present invention there is provided aflexible water gate for retaining water in a port, a canal or riverestuary comprising a flexible membrane and a gate operating mechanism,wherein the gate operating mechanism moves the flexible water gatebetween a closed position and an open position.

Preferably the flexible water gate further comprises a plurality ofsupport lines.

Preferably the support lines are selected from the group comprisingrope, chains, cord, straps or other suitable material capable ofproviding the required tensile strength.

Preferably the flexible membrane comprises Nylon. Alternatively theflexible membrane comprises Polyester, although any other impermeableflexible material may be employed.

Optionally the gate operating mechanism comprises a mechanical pulleysystem.

Alternatively the gate operating system comprises an inflatable chamberconnected to the flexible membrane and a pressurised gas control means.

Preferably the flexible water gate further comprises a plurality ofadjustment means, wherein the adjustment means connect the support linesand the mechanical pulley system.

Most preferably the support lines are connected to the mechanical pulleysystem in a substantially vertical plane, wherein when the mechanicalpulley system moves the support lines downwards within the saidsubstantially vertical plane the flexible water gate moves from theclosed position to the open position.

Preferably the adjustment means comprises a turn buckle adjustment screwwherein the turn buckle adjustment screw allows the tension within thesupport lines to be varied.

Preferably the mechanical pulley system is housed within recesseslocated on either side of the flexible membrane.

Preferably the flexible water gate further comprises a side sealassociated with each recess.

Preferably the flexible water gate further comprises a step associatedwith a canal, port or river bed on which is located a bottom seal, asupport means, a clamp and a fixing means wherein the support means,clamp and fixing means act to secure the bottom edge of the flexiblemembrane.

Most preferably the hydraulic pressure associated with the retainedwater acts to maintain the flexible membrane against the side seals andthe bottom seal so rendering the flexible water gate watertight.

Preferably the mechanical pulley system comprises two or more supportframes, a chain and a plurality of pulley wheels, wherein the chain andpulley wheels are arranged such that the chain provides at least twosubstantially vertical sections such that the sections of the chain thatfall within these vertical sections travel with the same velocity.

Preferably the support frames comprise a vertical post a plurality ofrollers wherein the rollers are free to move along the length of thevertical post.

Preferably the support frame further comprises one or more support guys,and one or more pile foundations, wherein the support guys connect thepile foundations to the vertical post.

Preferably the chain and the adjustable buckle screws are connected tothe rollers.

Preferably the mechanical pulley system is driven by an electric motor.

Preferably the gate operating system further comprises a buoy and a buoyanchoring means associated with either side of the flexible membrane.

Preferably the flexible membrane is connected to a buoy anchoring meansvia a plurality of eye connectors.

Preferably the flexible water gate further comprises a support means, aclamp and a fixing means wherein the support means, clamp and fixingmeans secure the bottom edge of the flexible membrane.

Most preferably the pressurised gas control means acts to inflate anddeflate the inflatable chamber with a gas so causing the flexible watergate to move between the closed and open positions, respectively.

Preferably the gas is selected from a group consisting of the followingair, oxygen, nitrogen and carbon dioxide.

According to a second aspect of the present invention there is provideda flexible flood control barrier comprising two or more flexible watergates in accordance with the first aspect of the present inventionwherein the flexible water gates are deployed so as to be located sideby side and operate independently as required during periods of floodtides.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will now be described by way ofexample only with reference to the accompanying figures, in which:

FIG. 1 presents a schematic illustration of a flexible water gate inaccordance with an aspect of the present invention;

FIG. 2 presents a plan elevation of the support frame and thefoundations employed by the flexible water gate of FIG. 1;

FIG. 3 presents a side elevation of a seal for the lower side of theflexible water gate of FIG. 1;

FIG. 4 presents a schematic illustration of a pulley mechanism employedto operate the flexible water gate of FIG. 1; and

FIG. 5 presents a:

(a) side view, with equal water levels, of an alternative flexible watergate;

(b) side view, with flood water levels, of the alternative flexiblewater gate; and

(c) perspective view of flood control barrier comprising two alternativeflexible water gates,

in accordance with an aspect of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 presents a schematic illustration of a flexible water gate 1incorporated with a canal system 2 containing a vessel 3. The flexiblewater gate 1 can be seen to comprise a flexible membrane 4 made fromeither Nylon or Polyester, a plurality of gate ropes 5, two supportframes 6 each housed within a support frame recess 7 and two pilefoundations 8 associated with each support frame 6.

Further detail of the support frames 6 and support frame recesses 7 ispresented in FIG. 2. The support frame recess 7 comprises a Neopreneseal 9 located on the low water side of the flexible water gate 1.

The support frame 6 comprises a vertical post 10, a plurality of rollers11 mounted on the vertical post 10, two support guys 12 and a pluralityof turn buckle adjustment screws 13. The flexible water gate 1 isattached to the support frame 6 via the gate ropes 5. A particular gaterope 5 connects to one end of a turn buckle adjustment screw 13. Theopposite end of the turn buckle adjustment screw 13 is thereafterconnected to a roller 11.

By tightening the turn buckle adjustment screw 13 tension is applied tothe flexible water gate 1. The hydraulic pressure associated with theretained water causes the flexible membrane 4 to press against theNeoprene seal 9 so forming the required watertight seal along the sidesof the flexible water gate 1.

In an alternative embodiment a support strut (not shown) may be deployedbetween the support frame recess 7 and the flexible membrane 4, on theretained water side of the flexible water gate 1. The addition of such asupport strut improves the efficiency of the Neoprene seal 9particularly in times of increased water levels on the low water side ofthe flexible water gate 1.

FIG. 3 presents the means for providing the watertight seal along thebottom of the flexible water gate 1. The lower side of the flexiblemembrane 4 is attached to a support tube 14. The support tube 14 is thenheld in place by a clamp 15 that is fixed to the canal floor 16 by afixing pile 17. A further Neoprene seal 18, incorporated within a step19 engineered on the canal floor 16, then provides the requiredwatertight seal in a similar fashion to that described above. Hydraulicpressure associated with the retained water causes the flexible membrane4 to press against the Neoprene seal 18 so forming the requiredwatertight seal along the bottom of the flexible water gate 1.

The flexible water gate 1 moves between a closed and open position underthe action of an electric motor driven pulley system 20 shownschematically in FIG. 4. The pulley system 20 comprises a continuouschain 21 that interacts with six pulley wheels 22 so as to provide fourvertical sections 23, 24, 25 and 26, and two horizontal sections 27 and28 that cross over on the canal floor 16. The orientation of thevertical sections 23 and 24 are such that they move in the same sense,either both up or both down. Similarly the vertical sections 25 and 26are so inter related.

By attaching the rollers to either vertical sections 23 and 24 orvertical sections 25 and 26 of the chain 21′ allows for the flexiblewater gate 1 to be moved between the closed and open position under thecontrol of the electric motor, as appropriate. As the flexible watergate 1 moves towards the open position the retained water is released soallowing the water levels on either side of the flexible water gate 1 toequalise.

FIG. 5 presents an alternative embodiment of the flexible water gate 29.In particular FIG. 5( a) presents a side view of a single flexible watergate 29, with equal water levels on alternative sides of the gate 29.FIG. 5( b) presents a side view of the single flexible water gate 29during a flood water situation such that the water levels on alternativesides of the gate 29 are no longer equal.

The flexible water gate 29 can be seen to comprise a flexible membrane4, an air chamber 30, buoys 31 located at either side of the flexiblemembrane 4 and an anchor cable 32 associated with each buoy 31. Theflexible membrane 4 is attached at either end to an anchor cable 32 viaa plurality of eye connectors 33.

In this particular embodiment the operation of the flexible water gate29 depends on the upper edge being buoyant therefore pulling theflexible membrane 4 tight. To engage the flexible water gate 29, air ispumped into the air chamber 30 so as to create a positive uplift on thegate 29. Similarly to disengage the flexible water gate 29 thepressurised air within the air chamber 30 is released allowing thestructure to sink to the seabed.

As the outer water level increases the differing hydrostatic forces willcause the flexible membrane 4 to lean towards the coastline as shown inFIG. 5( b). However, as the length of the flexible membrane 4 does notchange significantly the buoyant air chamber 30 is pulled downwards.This downwards motion acts to increase the upward force so tending topull the flexible membrane 4 back from its leaning position. Equilibriumis then established between the difference in head of water and theincreased buoyancy, thereby providing stability to the flexible watergate 29.

The flexible water gate 29 is particularly suited to helping in addressthe potential flooding of coastal areas. By arranging two or moreflexible water gate 29 end to end a flexible flood control barrier 34can be constructed, as presented in a perspective view in FIG. 5( c).

The flexible flood control barrier 34 is not intended to be watertightas there will be leakage between individual flexible water gates 29.However, the effects of such leakage is of reduced significance due tothe fact that the tidal water levels are time dependant and willtherefore eventually reduce with the ebbing tide.

Although the flexible flood control barrier 34 is located in position atall times, during normal tide conditions the location will only beevident by the presence of the buoys 31 anchored to the river bed. Asthe flexible membranes 4 are connected to associated anchoring cablesthe position of each individual flexible water gate 1 can beindependently controlled. When not required the flexible membranes canall be moved to their relevant storage positions on the river bed.

The presence of the buoyant air chambers 30 within the flexible floodcontrol barrier 34 provides an added advantage for such a system in thatas this design is flexible it provides an energy absorbing physicalbarrier to the wave action and any floating debris.

Aspects of the present invention have the advantage that they provide aflexible water gate for use in a port, canal or river estuary that isboth economical to build and install as well as providing a watertightbarrier. By employing a non-biodegradable flexible membrane the need forsubsequent maintenance is reduced, while the overall lifetime of thegate is increased, as compared to those previously described in thePrior Art.

The flexible water gate also has the further advantage that it is lightand compact and so is easy to transport over long distances and soeasier to deploy in areas with poor accessibility.

A yet further advantage of the flexible water gate is that it does notrequire the same engineering skill levels as required for theinstallation of the other gate designs taught in the Prior Art.Therefore, the flexible water gate reduces the disruption caused toports, canal and river estuaries during initial installation andmaintenance work.

Employing one or more flexible water gate 29 to produce a flexible floodcontrol barrier 34 has several advantages over exiting flood barriersystems. This system removes the requirement for substantial civilengineering works to be carried out and the installation of concretecaissons. The flexible flood control barrier 34 is thereforesignificantly more cost efficient and has less of an environmentalimpact than existing systems.

When not in use the flexible membranes of the flexible water gates canbe stored in the open position such that they are located on theriverbed. At such time they provide unrestricted access to marinevessels.

The foregoing description of the invention has been presented forpurposes of illustration and description and is not intended to beexhaustive or to limit the invention to the precise form disclosed. Thedescribed embodiments were chosen and described in order to best explainthe principles of the invention and its practical application to therebyenable others skilled in the art to best utilise the invention invarious embodiments and with various modifications as are suited to theparticular use contemplated. Therefore, further modifications orimprovements may be incorporated without departing from the scope of theinvention herein intended.

1. A flexible water gate for retaining water in a port, a canal or ariver estuary comprising a unitary flexible membrane having a firstsurface, a second surface, a first side and a second side; a gateoperating mechanism that moves the flexible membrane between a closedposition and an open position, wherein the flexible membrane is loweredfrom the closed position to the open position, wherein in the openposition the flexible membrane is stored on the bed of the port, canalor river estuary to provide unrestricted access to said port, canal orriver estuary; a first recess located at the first side and a secondrecess located at the second side of the flexible membrane; and a firstside seal and a second side seal associated with the first recess andthe second recess, respectively, wherein the first and second side sealsare located on the low water side of the flexible membrane such thatwhen the flexible membrane is in the closed position a hydraulicpressure associated with a retained water acts against the first surfaceof the flexible membrane to maintain the second surface of the flexiblemembrane against the first and second side seals forming a watertightseal along each of the first and second sides of the flexible watergate; wherein the gate operating mechanism comprises a mechanical pulleysystem and a plurality of adjustment means and a plurality of supportlines, wherein the plurality of adjustment means connect the pluralityof support lines to the mechanical pulley system.
 2. The flexible watergate of claim 1 wherein the plurality of support lines are connected tothe mechanical pulley system and orientated in a substantially verticalplane, wherein operation of the mechanical pulley system moves theplurality of support lines within the substantially vertical plane andmoves the flexible membrane from the closed position to the openposition.
 3. The flexible water gate of claim 1 wherein each of theplurality of adjustment means comprises a turn buckle adjustment screwand wherein the turn buckle adjustment screw allows a variable tensionwithin the support lines.
 4. The flexible water gate of claim 1 whereinthe mechanical pulley system comprises a chain and a plurality of pulleywheels, wherein the chain and the plurality of pulley wheels arearranged such that the chain provides at least two substantiallyvertical sections and wherein the two substantially vertical sectionstravel with the same velocity; wherein the mechanical pulley systemfurther comprises two or more support frames, the two or more supportframes comprising a vertical post and a plurality of rollers wherein theplurality of rollers move along a length of the vertical post; andwherein the two or more support frames further comprise one or moresupport guys and one or more pile foundations, such that the one or moresupport guys connect the one or more pile foundations to a verticalpost.
 5. The flexible water gate of claim 1 wherein the support linesare selected from the group consisting of rope, chain, cord and straps.6. A flexible water gate for retaining water in a port, a canal or ariver estuary comprising a unitary flexible membrane having a firstsurface, a second surface, a first side and a second side; a gateoperating mechanism comprising a mechanical pulley system, that movesthe flexible membrane between a closed position and an open position,wherein the flexible membrane is lowered from the closed position to theopen position; a first recess located at the first side and a secondrecess located at the second side of the flexible membrane; a first sideseal and a second side seal associated with the first recess and thesecond recess, respectively, wherein the first and second side seals arelocated on the low water side of the flexible membrane such that whenthe flexible membrane is in the closed position a hydraulic pressureassociated with a retained water acts against the first surface of theflexible membrane to maintain the second surface of the flexiblemembrane against the first and second side seals forming a watertightseal along each of the first and second sides of the flexible watergate; and a plurality of adjustment means and a plurality of supportlines, wherein the plurality of adjustment means connect the pluralityof support lines to the mechanical pulley system.